Proper control of cell migration and cell polarity is essential for proper vertebrate development. Inappropriate activation of developmental programs in an adult is linked to metastasis during tumor progression. Also, loss of proper cell migration during early development can lead to birth defect such as neural tube defects, including spina bifida. Thus, this proposal focuses on the establishment of cell polarity and cell migration during early development. A better understanding of the molecular control of cell migration during development, should lead to a better understanding of the root causes of birth defects and the mechanism of metastasis, and hopefully will aid in the prevention or treatment of these conditions.